Secondary battery

Abstract

A secondary battery includes: an electrode assembly including a first electrode plate, a second electrode plate, and a separator; a case accommodating the electrode assembly; a cap plate coupled to the case and having a terminal hole passing therethrough; a terminal over the terminal hole in the cap plate; a current collecting member electrically connecting the electrode plate and the terminal; and an insulating member insulating the cap plate and the terminal from each other and insulating the cap plate and the current collecting member from each other. At least one of a surface of the cap plate contacting the insulating member and a surface of the terminal contacting the insulating member has an unevenness formed thereon.

What is claimed is: 
     
         1 . A secondary battery comprising:
 an electrode assembly comprising a first electrode plate, a second electrode plate, and a separator;   a case accommodating the electrode assembly;   a cap plate coupled to the case and having a terminal hole passing therethrough;   a terminal over the terminal hole in the cap plate;   a current collecting member electrically connecting the electrode assembly and the terminal; and   an insulating member insulating the cap plate and the terminal from each other and insulating the cap plate and the current collecting member from each other,   wherein at least one of a surface of the cap plate contacting the insulating member and a surface of the terminal contacting the insulating member has an unevenness formed thereon.   
     
     
         2 . The secondary battery of  claim 1 , wherein the insulating member is integrally formed with the cap plate and the terminal through an insert injection process. 
     
     
         3 . The secondary battery of  claim 1 , wherein at least one of the surface of the cap plate contacting the insulating member and the surface of the terminal contacting the insulating member has nano-anchors formed thereon and on a smaller scale than the unevenness. 
     
     
         4 . The secondary battery of  claim 1 , wherein the cap plate has a coupling hole passing therethrough and arranged around the terminal hole, and
 wherein the insulating member has a first portion insulating the cap plate and the terminal from each other above the cap plate, a second portion insulating the cap plate and the current collecting member from each other below the cap plate, and a third portion filled in the coupling hole and connecting the first portion and the second portion to each other.   
     
     
         5 . The secondary battery of  claim 1 , wherein the unevennesses are grooves in the surface of the cap plate contacting the insulating member. 
     
     
         6 . The secondary battery of  claim 1 , wherein the unevennesses are grooves in the surface of the terminal contacting the insulating member. 
     
     
         7 . The secondary battery of  claim 1 , wherein the unevennesses are grooves in the surface of the cap plate contacting the insulating member and the surface of the terminal contacting the insulating member. 
     
     
         8 . The secondary battery of  claim 1 , wherein the unevennesses have a shape of a hexahedron or a cylinder. 
     
     
         9 . The secondary battery of  claim 8 , wherein, when the unevennesses are formed in the shape of the hexahedron, horizontal and vertical lengths thereof are in a range of 500 μm to 2 mm. 
     
     
         10 . The secondary battery of  claim 8 , wherein, when the unevennesses are formed in the shape of a cylinder, the unevennesses have a diameter in a range of 500 μm to 2 mm. 
     
     
         11 . The secondary battery of  claim 1 , wherein the case has a pipe shape having both ends open,
 wherein the cap plate comprises a first cap plate and a second cap plate, the first cap plate being coupled to one end of the case, the second cap plate being coupled to the other end of the case,   wherein the terminal comprises a first terminal and a second terminal, the first terminal being on a side of the first cap plate, the second terminal being on a side of the second cap plate,   wherein the current collecting member comprises a first current collecting member and a second current collecting member, the first current collecting member electrically connecting the first electrode plate and the first terminal, the second current collecting member electrically connecting the second electrode plate and the second terminal,   wherein the insulating member comprises a first insulating member and a second insulating member, the first insulating member insulating the first cap plate and the first terminal from each other and the first cap plate and the first current collecting member from each other, the second insulating member insulating the second cap plate and the second terminal from each other and the second cap plate and the second current collecting member from each other, and   wherein the unevennesses are formed on at least one of a surface of the first cap plate contacting the first insulating member, a surface of the first terminal contacting the first insulating member, a surface of the second terminal contacting the second insulating member, and a surface of the second terminal contacting the second insulating member.